The use in printing inks of polyamide resins and of acrylic resins is known. The use of polyamide resins in inks imparts to them excellent bond strength, adhesion, gloss, and printability. They are not, however, useful for aqueous inks because they are not water-dispersible. On the other hand, acrylic resins can be made water-dispersible, but they do not impart to inks the desirable properties obtainable with polyamides. These two resins are generally incompatible, since upon mixing solutions of the two they will separate into different phases.
Ideally a copolymer of these two incompatible polymers would result in an excellent water-based ink but such copolymers have not been readily produced.